Q: How you define Hypereosinophilic syndromes (HES)?
Answer: Absolute Eosinophilic Count ≥1500/microL on two occasions ≥1 month apart plus organ dysfunction attributable to eosinophilia. An important distinction to remember is if the clinical condition with hypereosinophilia can be explained by any other mechanism should not be labeled as HES.
A complete description of this syndrome is beyond the scope of this pearl, but we strongly suggest to read this article:
Florence E Roufosse, Michel Goldman & Elie Cogan
Orphanet Journal of Rare Diseases - volume 2, Article number: 37 (2007)
Valent P, Klion AD, Horny HP, et al. Contemporary consensus proposal on criteria and classification of eosinophilic disorders and related syndromes. J Allergy Clin Immunol 2012; 130:607.